Key

In the KIELER project we are conducting regular code reviews of (possibly) all of our sources. To make things easier, we do software assisted reviews in Crucible.

Review Scheme

Reviews are scheduled for every thursday. In the weekly KIELER meeting one author and two reviewers are chosen.

On this Page

Table of Contents

Design Reviews

Design reviews are scheduled during our various project meetings. For each review, one author and at least two reviewers (though not more than three) are selected. Design reviews take place during special design review meetings. The author's job is to prepare for the meeting by doing the following:

Choose the classes that are to be reviewed.

Prepare a meeting page in our Wiki.

Fill the meeting page with all information necessary for the reviewers to prepare for the code review. That may include class or sequence diagrams. You may also want to take this opportunity to add documentation about the reviewed bits and pieces to the Wiki and link to that documentation from the meeting page.

Now the reviewers look at your meeting page and through the code that is to be reviewed. During the meeting, you will discuss the comments of the reviewers and take notes of all change decisions in the meeting notes. After the review, the author goes through all decisions and gets the changes done, noting so in the notes. The author also adds a tag to the reviewed classes to mark them as design reviewed (see below).

Code Reviews

Code reviews are scheduled during our various project meetings. For each review, one author and at least two reviewers (though not more than three) are selected. The author's job is then to do as follows:

Write a comment if there is something that needs to be improved and mark the comment as defect

If you want to put more emphasis in your opinion, create a corresponding Jira issue for the defect directly from Crucible

Write a comment if there is anything that is not understood

Review Meeting

The week after, on Thursday, the review meeting takes place. In the Meeting the following exciting things happen

The moderator welcomes the author and the reviewers to the meeting

The moderator asks for further general remarks

The moderator reads all comments aloud

If there are any questions, reviewers or the author interrupt the moderator and start discussing

The moderator keeps the discussion brief

Finally, the moderator asks if any further remarks have arisen during the review

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What goes into a code review?

If you have never reviewed source code before, you might wonder what to write into the review. Here's a few things you might look out for:

Is the code understandable as it is? If not, try to find out what is wrong. The problems may be that comments are missing or misleading, that the code has an awkward structure, or that it is even outright wrong.

Does every class, every field and every method has a Javadoc comment?

Do the field and variable names make sense? For example, loop variables are often named "i" or "j", while they should actually be called "fooArrayIndex" or something similar.

Does the code contain logic bugs? For example, dead code that never gets executed or null pointer problems?

Basically, look out for anything that strikes you as odd or problematic.

After the Review

After the review it is up to the author to finish any tasks that have been risenrespond to all comments the reviewers gave.

The author goes through all comments in Crucible and leaves a note about his decision

The author may schedule a followup meeting which is only held online to review for example auxiliary classes

The author adds a tag to the reviewed classes to mark them as reviewed according to the proposed rating (see below)

Code Tags

Design Reviews

When classes are ready for a design review, they should be marked with the following tag:

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@kieler.design proposed <comment>

After the design review has been performed, the same tag can be used to mark the reviewed classes by removing the proposed modifier and adapting the comment. The comment should contain the date of the design review (yyyy-mm-dd) and the login names of the attendees.

Code Reviews

All classes have initial code review rating red. The first code review lifts them to yellow, and the second one to green. The following tag marks classes that are ready for the first code review:

Code Block

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@kieler.rating proposed yellow <comment>

After the code review has been performed, the same tag can be used to mark the reviewed classes by removing the proposed modifier and adapting the comment. Similarly, the second code review can be marked using the green modifier. The comment should contain the date of the code review (yyyy-mm-dd), the login names of the attendees, and the ID of the code review in Crucible (such as KI-15).

Review Overview Page

The design and code review tags are processed automatically using a custom doclet during Bamboo builds. The result is displayed in a generated HTML page:

Tag Syntax

The complete syntax of the available tags is as follows:

Code Block

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@kieler.design [proposed] yyyy-mm-dd comment
Marks a class as design-reviewed or to be design-reviewed. For proposed classes, the
comment should mention the login name of the person proposing the class to be reviewed.
For reviewed classes, the comment should include the names of the reviewers.
@kieler.rating [proposed] <yellow|green> yyyy-mm-dd comment
Marks a class as code-reviewed or to be code-reviewed. For proposed classes, the
comment should mention the login name of the person proposing the class to be reviewed.
For reviewed classes, the comment should include the names of the reviewers as well as
the ID of the review in Crucible (for instance "KI-15").
@kieler.ignore comment
Marks a class as to be ignored in the code rating statistics. The comment should provide
an explanation of why the class is ignored.

To be compatible with past tags, the doclet is actually quite flexible in terms of what it still accepts. However, it is good practice to follow these recommendations.